The standard method for locating a driverless vehicle at a predetermined location is by means of a locating pin such as that illustrated in FIG. 15 of U.S. Pat. No. 3,858,626. A locating pin of that type has an accuracy of about 0.015 inches. In automated assembly line systems, there is a need for substantially greater accuracy. The problem solved by this invention is how to precisely cause a vehicle which may have a length of 10 to 15 feet stop at a location with accuracy of .+-.0.005 inches in three planes.